|Publication number||US7635901 B2|
|Application number||US 10/582,521|
|Publication date||Dec 22, 2009|
|Filing date||Dec 13, 2004|
|Priority date||Dec 19, 2003|
|Also published as||DE602004011637D1, DE602004011637T2, EP1708958A1, EP1708958B1, US20070126068, WO2005061375A1|
|Publication number||10582521, 582521, PCT/2004/3217, PCT/FR/2004/003217, PCT/FR/2004/03217, PCT/FR/4/003217, PCT/FR/4/03217, PCT/FR2004/003217, PCT/FR2004/03217, PCT/FR2004003217, PCT/FR200403217, PCT/FR4/003217, PCT/FR4/03217, PCT/FR4003217, PCT/FR403217, US 7635901 B2, US 7635901B2, US-B2-7635901, US7635901 B2, US7635901B2|
|Original Assignee||Commissariat A L'energie Atomique|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Non-Patent Citations (1), Referenced by (3), Classifications (21), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The invention relates to a microcomponent comprising a hermetically-sealed cavity, delineated by a cover in which at least one hole is formed, and, on the cover, a sealing layer sealing the microcavity hermetically.
Hermetic encapsulation of electromechanical microsystems is necessary for several reasons. Dust and humidity can, in particular, disturb operation of the moving parts and the electric contacts can be impaired by the oxygen of the ambient air.
Conventionally, electromechanical Microsystems are enclosed in a hermetically-sealed microcavity delineated by a cover. A known method for production of a hermetic cover is represented in
Fabrication by means of a sacrificial layer 3 gives rise to two problems, among other, i.e. an insufficient tightness of sealing and a lengthy time required for the removal step of the sacrificial layer 3, in particular in the case of large covers 4.
To achieve hermetic sealing of the cover 4, the holes 5 are in fact typically small and localized in zones of the sacrificial layer 3, and consequently of the microcavity 6, that present a small thickness, as represented in
The document DE10005555 describes a microcomponent comprising a hermetic cavity delineated by a cover. The cover is formed by bottom and top layers respectively comprising holes offset with respect to one another. The holes of the top layer are sealed by closing layers, preferably made of aluminium, arranged on the bottom layer, under the holes. The bottom layer thus acts as continuous solid support for the sealing layers. When the sealing layers are made of aluminium, a temperature of 660° C. is applied to melt the sealing layers The sealing layers are located entirely above the top layer. The holes of the top layer are then filled by an additional sealing layer covering the top layer.
It is one object of the invention to remedy these shortcomings and, in particular, to achieve hermetic sealing of a microcavity while reducing the time required to produce the microcavity.
According to the invention, this object is achieved by the appended claims and in particular by the fact that the microcomponent comprises, under the sealing layer, a plug covering the hole and a part of the cover over the periphery of the hole, the plug being made from a material that is able to undergo creep deformation.
It is a further object of the invention to provide a method for production of a hermetically-sealed microcavity of a microcomponent, successively comprising
Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention given as non-restrictive examples only and represented in the accompanying drawings, in which:
As represented in
The plug can be achieved by deposition of a viscous polymer solution covering the cover 4, followed by etching of the layer thus obtained to delineate the plug 8 laterally.
It is well known that, for polymers, the temperatures applied during the method must not exceed 450° C. The use of polymers is then particularly suitable for methods performed at low temperature, i.e. methods having a maximum temperature comprised for example between 300° C. and 450° C., or even less.
In another embodiment the plug 8 can be produced by a method of the sol-gel type or by cathode sputtering, so as to obtain, for example, a phosphosilicate glass (PSG).
As represented in
To prevent the material forming the plug 8 from depositing inside the microcavity 6, the dimension of the hole 5 is preferably smaller than 5 micrometers. The hole 5 can for example have a substantially rectangular cross-section of 3 μm by 5 μm. As etching of the sacrificial layer 3 is slowed down by reduction of the size of the hole 5, the microcomponent preferably comprises a plurality of holes 5, in particular in the case of a cover 4 of large size. In
The plug 8 is not necessarily hermetic. In particular, the plug can be formed by a porous material, for example by a porous polymer. The porous material is, for example, a photoresist annealed at a temperature of more than 300° C. As illustrated in
The material of the sacrificial layer 3 can be a polymer, for example polyimide or a photoresist, enabling rapid etching, for example dry etching, or a material obtained by a sol-gel type process. The cover 4 and sealing layer 9 can be made of silicon dioxide (SiO2), silicon nitride (Si3N4) or metal. The cover 4 can for example be achieved by deposition of silicon dioxide having, for example, a thickness of 1.5 microns. The sealing layer 9 is preferably achieved by deposition of silicon nitride having a thickness of 2 microns for example.
The invention is not limited to the particular embodiments represented. In particular, there can be any number of holes 5. A single layer forming several plugs 8 can if required be associated with several holes 5.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7919362 *||Apr 5, 2011||Commissariat A L'energie Atomique||Method for preparing a cover for protecting a component on a substrate|
|US8367929||Feb 5, 2013||Commissariat A L'energie Atomique Et Aux Energies Alternatives||Microcavity structure and encapsulation structure for a microelectronic device|
|US20080180890 *||Jan 25, 2008||Jul 31, 2008||Commissariat A L'energie Atomique||Method for preparing a cover for protecting a component on a substrate|
|U.S. Classification||257/415, 257/419, 333/186, 257/E23.181, 257/420, 438/125, 438/48, 257/414|
|International Classification||H01L21/54, G01R33/09, B81B7/00, G01P1/02, H01L21/56, G01L1/12, H01L23/10|
|Cooperative Classification||B81C2203/0136, G01P1/023, B81C1/00293, B81C2203/0145|
|European Classification||G01P1/02B, B81C1/00C14C10|
|Jun 9, 2006||AS||Assignment|
Owner name: COMMISSARIAT A L ENERGIE ATOMIQUE, FRANCE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ROBERT, PHILIPPE;REEL/FRAME:018002/0879
Effective date: 20060424
|Mar 5, 2013||FPAY||Fee payment|
Year of fee payment: 4